Jesse c



J. C. KING.

ELECTRODE.

APPLICATION FILED 001.9. x912.

Patented Aug. 5, 1919.

mren/ar' Jesse 6'. may 4v To all whom it may concern Be it known that I, JEssE C. KING, a citizen of the United States, and resident of the city of Montreal, in the Province of Quebec and Dominion of Canada, have invented certain new and useful'lmprovements in Electrodes, of .which the following is a full, clear, and exact description.

This invention relates to improvements in electrodes for use in electric furnaces and the like.

It is well known that electrodes, which usually consist of carbon, waste or burn away quite rapidly at points remote from the active end, thus reducing the efliciency and life of the electrode. The carbon body becomes heated to very high temperatures for a considerable distance back from the end, and this heating renders the carbon more or less readily combinable with oxygen of the air or w1th other gases, with the result that the electrode burns away, thus reducing the sectional area and consequently altering the resistance and conductivity of the electrode.

The main object of my invention is to provide an electrode having on the outer surface thereof a thin coating of non-oxidizing material designed to protect the body of the electrode from comblnation with gases at all parts of the surface not in actual operation. I have found that a coating of finely ground magnesite is very suitable for plied in the manner described in my ppnding application, Serial No. 99,104, filed ay- 22nd, 1916. .After the. application of the protective coating, the electrode is preferably baked, sothat the core and the coating become for all practical purposes intel. llteferring to the drawing, which represents a cross sectional view of the electrode with the coating applied thereto, 11 designates the core or electrode proper of carbon havin thesurface 12 roughened by any suitab e means. The coating of magnesite Specification of Letters Patent.

this purpose, and the coating may be ap-- co-' STATES I PATENT OFFICE.

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ELECTRODE.

: Patented Aug. 5, 1919.

- Application filed October 9, 1917. Serial No. 195,576.

to a suitable fineness may be molded, pasted,

pressed or sprayed on to the roughened carbon core, and when suitably. hardened, this coating forms an impenetrable coating between the electrode and the gases of the furnace.

In some cases it may be desirable to use a binder consisting of a small proportion of pitch or other carbonaceous bonding material. When a small quantity of such a binder is used, it holds the coating during the baking process where it becomes thoroughly hardened. It will be understood that either pure magnesite, MgO, may be used, or commercial magnesite, the latter often containing impurities such as iron oxid, lime, etc.

If it is desired to mold the surface coating on to the carbon electrode, the latter ma be used'in a suitable mold as a core an the magnesite coating may be pressed into the mold around the core in the usual manner. If the magnesite coating is to be pasted on to the core, a trowel or other suitable implement may be used and the magnesite in plastic condition may be pasted on to the roughened surface 'of the core, in as even a manner as possible; To spray the coating on to the core, any suitable implement, plo ed.

aving thus described my invention, what I claim is An electrode comprising a carbon core having a roughened surface, and a coating of magnesite mixed with a carbonaceous binding material bonded or baked on the roughened surface.

In witness whereof, I have hereunto set my hand.

JESSE C. KING.

such as a cement gun, may be em- 

